Crest Audio PRO-9200 Amplifier Test Results

Crest power amplifier with extremely good performance indeed. Very low distortion at full power and averaging 0.05% at 3/4 power at all frequencies and load impedances. Clipping behaviour is excellent, and the ability to drive 2R loads 'continuously' (full power sine wave for greater than 10 seconds - one channel driven) certainly gives the amp a lot of muscle.

Lightweight aluminium casework and small case size with external fans (see images below) give the amp an incredibly large power to weight ratio. The amp is a single ended class G/H design and comfortably competes with class D designs in terms of size and weight, but with added performance and lower distortion. The circuitry is visibly similar to the Peavey CS4080HZ, but with a switched-mode power supply instead of a toroid, and higher rail voltages.

*2R performance was measured with one channel driven only, because excessive sine testing caused the power supply to go into overcurrent protect. However, at 2R the amp will comfortably deliver almost 4kW per channel, 100ms burst, both channels driven, without problems.

Freq

8R Performance

4R Performance

2R Performance

Watts

THD%

Watts

THD%

Watts

THD%

40Hz

1326

0.71

2167

0.49

3942*

0.79

1kHz

1300

0.52

2227

0.35

3960*

0.34

10kHz

1275

0.16

2162

0.99

3698*

1.10

All results taken with sine wave input into a resistive dummy load of 8, 4 and 2 ohms (where applicable), two channels simultaneously driven (unless otherwise stated), at the threshold of clipping. These results should be considered maximum 'continuous RMS' power ratings (>5 seconds). Distortion measurements, labelled THD%, are taken with an HP8903A audio analyser (80kHz Bandwidth).

1 Power to weight ratio is calculated by taking the average of the power measurements at 4 ohms, multiplying by the number of driven amp channels, and then dividing this value by the weight of the amplifier.

Click the images below for full-size versions

Description of Images:

Amplifier front

Amplifier internals showing the amp channel heatsinks towards the left and switched mode power supply towards the bottom right.

Closeup of the SMPS and primary and secondary smoothing capacitors.

Closeup of the amp channel heatsinks.

Rear of the amplifier. Note the externally-mounted case fans to save case depth.

1kHz sine wave, full power, 8R. Perfect.

10kHz sine wave, full power, 8R. Perfect.

40Hz sine wave, full power, 4R. Again, perfect.

40Hz sine wave, into clipping, 4R. This is the point where the clip limiter activates. Slanting of top and bottom of waveform suggests 50Hz power supply ripple, but this is considerably less than most designs.